Typically vehicles and/or machines include a fuel-powered engine providing mechanical power to a transmission. The transmission typically includes a plurality of selectable gear ratios that transfer the mechanical power from the engine to one or more loads. For example, the transmission may be configured to deliver mechanical power to one or more traction devices so as to propel the vehicle or machine. Hybrid vehicles and/or machines include one or more motor/generators operatively connected to the transmission. The motor/generators are selectively operated to provide extra mechanical power to the transmission, i.e., in addition to the engine, or to receive extra mechanical power from the transmission, i.e., from the engine. The received mechanical power may be converted into electrical power and stored for later use. Additionally, a hybrid vehicle or machine may be configured to selectively operate in a motor/generator only mode, i.e., the transmission may only receive mechanical power from the motor/generators.
U.S. Pat. No. 7,220,202 (“the '202 patent”) issued to Singh et al. discloses an electrically variable transmission. The transmission includes first and second planetary gear sets. An input member is continuously connected to the ring gear of the first planetary gear set and an output member is continuously connected to the carrier of the second planetary gear set. The transmission also includes a first motor/generator continuously connected to the sun gear of the first planetary gear set and a second motor/generator continuously connected to the sun gear of the second planetary gear set. The transmission also includes five torque transfer devices. Three torque transfer devices selectively interconnect components of the first and second planetary gear sets to one another, i.e., act as clutches. Two torque transfer devices selectively fix components of the first and second planetary gear sets to a housing, i.e., act as brakes.
The transmission of the '202 patent may be operable in different operating modes depending upon the combination of torque transfer devices that are engaged. However, because of the particular arrangement of the various components of the transmission, e.g., the motor/generators and the torque transfer devices, the transmission of the '202 patent may have a limited set of operating modes. As such, the transmission of the '202 patent may be limited in its applicability.
The present disclosure is directed to overcoming one or more of the shortcomings set forth above and/or other shortcomings in the art.